1. Field of the Invention
The present invention relates, in general, to an optical network terminal, and, more particularly, to an optical network terminal, which can prevent a laser diode from continuously emitting light and seizing time slots, allocated to other optical network terminals, due to a fault or malfunction.
2. Description of the Related Art
Generally, a passive optical network is one of optical subscriber construction schemes for providing an optical fiber-based high-speed service to businesses or normal homes, and may include a single Optical Line Terminal (OLT) and a plurality of Optical Network Terminals (ONTs) connected thereto.
A passive optical network may be constructed using a Time Division Multiplexing (TDM) scheme. In such a TDM passive optical network, in order to implement an upstream procedure that transmits data from ONTs to an OLT, a scheme is used in which respective time slots are allocated to a plurality of ONTs and each ONT transmits light to the OLT in its own time slot.
In the TDM passive optical network, the case where a laser diode that generates light continuously emits light due to a fault or malfunction of the ONT occurs. In this case, a problem arises in that the ONT in which the fault or malfunction has occurred seizes time slots of other ONTs of the passive optical network to which it belongs, as well as its own time slot, due to the continuous light emission, thus making it impossible to allow ONTs which perform normal operations to transmit data. Further, there is a problem in that the OLT cannot receive data from ONTs other than the ONT in which the fault or malfunction has occurred, so that it determines that all of the ONTs connected to the OLT are faulty.